In continuous ink jet printing, ink is supplied under pressure to a manifold region that distributes the ink to a plurality of orifices, typically arranged in a linear array(s). The ink discharges from the orifices in filaments which break into droplet streams. The approach for printing with these droplet streams is to selectively charge and deflect certain drops from their normal trajectories. Graphic reproduction is accomplished by selectively charging and deflecting drops from the drop streams and depositing at least some of the drops on a print receiving medium while other of the drops strike a drop catcher device. The continuous stream ink jet printing process is described, for example, in U.S. Pat. Nos. 4,255,754; 4,698,123 and 4,751,517, the disclosures of each of which are totally incorporated herein by reference.
In the ink jet printing art, the ability to print on non water receptive publication substrates with a water based fluid without the undesirable characteristics of mottling, crawling, or pinholing has long been a goal of printers using high resolution continuous ink jet equipment. Examples of these substrates include ultra violet curable coatings, heavy screen values above 30% applied by other printing processes, non cellulose substrates such as metal foil laminates, spun polyolefin, vinyls, acetates, and plastic impregnated papers. Previous and current water base recording fluids or inks used in this type of application sought to overcome this problem through the use of surfactants or surface active agents. This has met with only partial success in eliminating these problems. Another approach to resolving this problem has been the incorporation of polymeric materials in the ink. The amount of polymer required to produce acceptable images has historically resulted in inks with high viscosities, poor resolubility, and difficulties in printer operation.
It is seen then that there is a need for a water based recording fluid capable of producing uniform high quality images free of mottling, crawling, or pinholing defects, particularly on non water receptive publication substrates.